Railway axle brush contacting assembly



Oct. 27, 1970 L. FERRAZ 3,537,058

I RAILWAY AXLE BRUSH CONTACTING ASSEMBLY- Filed. Sept. 24, 1968 United States Patent Oifice Int. Cl. B60!) 35/00 H01r 39/10, 39/40 US. Cl. 339 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to brush contacting devices which are interposed between an axle box and the corresponding axle in an electric railway vehicle in order to avoid passage of the electric current through the axle bearings.

In accordance with the present invention in a brush contacting device of the kind above referred to, comprising brushes slidably carried by a non-rotating brushsupporting member and urged by spring means against the transverse end face of the axle, or against a contacting plate secured thereto, the brushes are disposed around an axial core carried by an outer end cover of the brushsupporting member, so as to form with the said cover a readily removable unit to which the brush-urging spring means are attached, in such manner that by removing the said unit, the brushes may be liberated from the spring means and therefore freely accessible.

In the annexed drawings:

FIG. 1 is an end view of a brush contacting device mounted on the axle box of an electric railway vehicle, the cover being supposedly removed.

FIG. 2 is a section taken along line II-II of FIG. 1. In this figure line II indicates the transverse section which corresponds to FIG. 1.

FIG. 3 is a fragmental section showing how the degree of wear of the brushes may be ascertained without removing the outer cover.

FIG. 4 reproduces a portion of FIG. 2 with the outer cover separated from the brush-supporting body.

Referring to FIGS. 1 and 2, reference numeral 1 designates one end of an electric railway vehicle axle. This axle supports bearings 2 which are retained outwardly in an axle box 3. The inner races of bearings 2 are clamped on each axle end 1 by means of an end cap 4 urged by screws 5 screwed into the transverse end face of the axle. Cap 4 has an outwardly directed cylindrical extension 4a which rotates with reduced clearance within an annular cover 6 secured to box 3 by means of bolts such as 7 (FIG. 1). This cover 6 is provided with sealing means 6a which cooperate with the circular periphery of extension 411 of cap 4.

The open end of extension 4a is closed by a plate 8 (FIG. 2) secured in position by means of screws such as 9 so as to rotate with axle 1. Plate 8 may be made of bronze.

A cylindrical brush-supporting body 10 is axially engaged into the annular cover 6, this body having an outward flange 10a which is secured against the outer face of cover 6 by screws 11. The supporting body 10 has three longitudinal bores 10b of rectangular cross-section regularly disposed about an axial bore 100 of hexagonal cross-section, as more particularly shown in FIG. 1. Bores 10b communicate by means of longitudinal slots with the axial bore 100.

In each bore 10b is slidably mounted a brush 12 adapted to bear against plate 8 by its inner end face,

3,537,058 Patented Oct. 27, 1970 while its outer end face is at an angle to the brush axis and has a metallic covering 13 integral with an outwardly projecting tongue 13a which is slidably received in a slot 10d of the bore 10b under consideration, this slot only opening on the outer side of body 10 in such manner that its inner end may form an abutment which limits displacement of the brush 12 towards the axle end. Each brush 12 further comprises two flexible braided conductors 14 the free ends of which are clamped under screws 15 screwed into the outer transverse end face of body 10.

The device further comprises an outer cup-shaped cover 16 applied against the outer side of flange 10a of body 10 and maintained in position by screws such as 17. The central portion of this cover has an inwardly directed tubular extension or core 16a of hexagonal crosssection adapted to fit with a small clearance within the axial bore of body 10, the arrangement being such that three of the outer lateral sides of extension 16a be situated in front of the slots provided between the three rectangular bores 10b and the hexagonal axial bore 100, as clearly shown in FIG. 1. On each of the three aforesaid sides there is disposed a spring 18 formed of a steel strip which tends to coil on itself and to impart a substantially uniform reaction to the parts which stop the displacement of its already coiled portion 18a. The outer end of each spring 18 is secured to the corresponding side of extension 16a by means of a rivet 19 situated near the free end of this extension. The strip extends in straight line on a portion of the length of the side under consideration while its coiled portion 18a bears against the metallic covering 13 of the brush 12 disposed in the corresponding rectangular bore 10b. Of course the width of the steel strip is slightly lower than the width of the aforesaid slot. It will be understood that owing to the tendency of the spring to coil on itself, brush 12 is applied against plate 8 with a substantially uniform contacting pressure, in a manner which is per se well known in brush holders for electric machines.

The outer cover 15 further comprises three inwardly directed bosses 13b of substantially cylindrical shape, each being situated in front of one of brushes 12 in the vicinity of one of the corners of the rectangular crosssection thereof as clearly shown in FIG. 1. Each boss 16b has a cylindrical bore (see FIG. 3) the axis of which is parallel to the general axis of the device.

It will be understood that the brushes 12 and the braided conductors 14 associated therewith form a current conducting passage of bridge between the axle 1 and the axle box 3, this passage or bridge short-circuiting the roller bearings 2 which are no more liable to be damaged. It is of course assumed that the axle box 3 is directly connected with the frame of the vehicle frame from an electrical point of view. Owing to the obliquity of the metallic covering 13 provided on the outer end of each brush 12, this outer end is pushed outwardly against the wall of the corresponding bore 10b opposed to the axial extension or core 16a. Since the inner end of the brush is itself urged outwardly by frictional forces, each brush is wholly maintained against the aforesaid wall, which avoids vibrations oscillations and the like.

When it is desired to check the wear of the brushes, this may be done without removing cover 16 by merely driving through the bores 16c of the successive bosses 16b a rod or gauge 20 provided with appropriate graduations as shown in FIG. 3. This rod engages the metallic covering 13 and since it is positively guided within the boss, the obliquity of the covering has no influence on the measure.

When it is desired to have access to the brushes, as for instance for changing them, the outer cover 16 is removed as shown in FIG. 4. The three springs 18 coil down to their securing rivets 19 where they are retained in position. The brushes 12 are fully exposed and it is then possible to extract them from body by means of their braided conductors 14 after removing screws 15. When fresh brushes have been disposed in bores 10b, cover 6 is merely re-mounted against the outer side of body 10. During this operation the springs 18 are uncoiled until they assume the position shown in FIG. 2. It is to be noted that the brushes may be changed individually if desired.

By using three screws 17 any incorrect mounting of the outer cover 16 is fully eliminated and the springs 1818a are automatically disposed in front of each brush. In any case if an operator attempted to mount cover 16 at an incorrect angular position, the outer heads of rivets 19 could not be engaged into the axial bore 10c of body 10,

and the operator would therefore be compelled to dispose the cover in such manner that these heads be in front of the slots provided between bore 100 and bores 10b.

When it is desired to expose the end of axle 1, as for instance for inspection of the adjacent bearing 2, the outer cover 16 is first removed, as above explained, screws 11 are unscrewed and the brush-supporting body 10 may be removed. If this body is held with its inner face more or less directed downwardly, brushes 12 are not liable to escape, since they are retained by tongues 13a.

=I claim:

1. A brush contacting device adapted to be interposed between an axle box and the corresponding axle in an electric railway vehicle comprising a brush-supporting member secured to the axle box, said member having an inner end face and an outer end face, with said inner end face disposed in front of said axle end; brushes slidably carried by said brush-supporting member so as to be movable towards said axle end, longitudinally with respect thereto, each brush having a longitudinal axis, an inner end and an outer end, with said inner end facing said axle end; an outer cover removably secured to the outer end face of said brush-supporting member; an axial core carried by said outer cover and axially disposed within said brush-supporting member; and brushurging spring means carried by said axial core and acting on said brushes to urge same towards said axle end.

2. In a contacting device as claimed in claim 1, said core having a lateral side and said spring means being in the form of resilient coiled strips with a coiled portion and an outer end, each having its coiled portion applied against the outer end of a brush, and its outer end secured to the lateral side of said axial core.

3. In a brush contacting device as claimed in claim 2, said axial core having a first end secured to said outer cover and a second end facing said axle end; the outer end of eachof said resilient coiled strips being secured to said core in the vicinity of the second end thereof;

and said brush-supporting member being in the form of a body having an axial bore to receive said axial core and a number of brush-guiding bores disposed around said axial bore in parallel relation thereto, each to slidably receive one of said brushes, and elongated slots forming a passage for each of said resilient coiled strips between said axial bore and each of said brush-guiding bores.

- 4. In a contacting device as claimed in claim 3, adapted for use with an axle box having a substantially vertical outer side, normally closed by a removable axle box cover, said brush-supporting member having a flange so as to be removably secured against said outer side of said axle box in lieu of said axle box cover.

5. In a brush contacting device as claimed in claim 1, said outer cover having in front of each of said brushes an elongated guiding bore parallel to the longitudinal axes of said brushes and offset with respect to the one of said spring means which corresponds to each brush in such manner that a gauging rod passed through each of said guiding bores may engage the outer end of one of said brushes.

6. In a brush contacting device as claimed in claim 1, said brush-supporting member being in the form of a body having an axial bore to receive said axial core; a number of brush-guiding bores disposed around said axial bore in parallel relation thereto, each to slidably receive one of said brushes; and elongated slots each forming a passage for said spring means between said axial bore and one of said brush-guiding bores.

7. In a brush contacting device as claimed in claim 1 a cup-shaped member secured against said axle end to rotate therewith, said cup-shaped member opening outwardly of said axle end and having a cylindrical periphery; sealing means interposed between said axle box and the periphery of said cup-shaped member; and a contacting plate secured to said cup-shaped member so as to form a cover therefor, said contacting plate having a flat outer side to slidably receive the inner ends of said brushes.

References Cited UNITED STATES PATENTS 2,064,642 12/1936 Bossart 246-8 2,248,394 7/1941 Sorensen 339-5 2,685,621 8/1954 Callender 191-45 2,814,537 11/1957 Brittain 308-180 XR ARTHUR L. LA POINT, Primary Examiner H. BELTRAN, Assistant Examiner US. Cl. X.R. 

